Warp Threads Research Articles

Cyclic twill-woven objects

Classical (or biaxial) twill is a textile weave in which the weft threads pass over and under two or more warp threads, with an offset between adjacent weft threads to give an appearance of diagonal lines. This paper introduces a theoretical framework for constructing twill-woven objects, i.e., cyclic twill-weavings on arbitrary surfaces, and it provides methods to convert polygonal meshes into twill-woven objects. It also develops a general technique to obtain exact triaxial-woven objects from an arbitrary polygonal mesh surface.

Kimono Mode and Marketing: Popular Textiles for Women in Early Twentieth Century Japan

Meisen was a commercial term for a popular, widely distributed textile used by lower- and middle-class women and children for everyday wear (kimono and haori) or special or festive occasions, and by many people for coverlets and sitting cushions. The cloth was relatively inexpensive and therefore popular among a new and actively growing market sector during the first half of 20th century Japan - women of the working and middle classes. Meisen textiles – a silk or synthetic silk cloth woven with warp or weft threads that were patterned prior to the weaving process, displayed bright colors and bold designs that offered wearers a new identity. The aesthetics of this textile, considered “moderne” or “mod,” set meisen designs apart from the rest of Japanese traditional textiles, generally known for their sophistication and subtlety. The conspicuous popularity of these designs puzzles today’s viewers, both Japanese and Western. Written materials from the late Edo period until the early 1960s that promoted meisen and beauty posters published by Japanese textile makers illustrate how Westernization and industrialization pulled their country out of a medieval social structure into a modern capitalist one, wherein new marketing techniques emerged. Meisen textiles provide us with insight into Japan’s social and cultural climate during an interesting period of its recent history.

Development of fluidic weft insertion sensors

Measuring the speed of weft insertion into the shed of warp threads on a jet loom is a difficult problem, sometimes described as nearly impossible to solve. A solution was found by the author in an inversion of the basic principle of shuttle-less air-jet loom, i.e. using the dragging action between the weft and air flow. Initially, the analogy went as far as using also an air jet – issuing from a nozzle through which the weft passes – as the flow influenced by the weft motion. Recent studies, described in this paper, have shown that better performance is obtained by the weft/air interaction in long, small-diameter channels.

The effect of yarn twist direction on the formability of woven fabrics

This experimental work examines the influence of the yarn twist on the formability of a woven fabric. Consideration is given to the phenomenon of bedding between warp and weft yarns, as affected by the local helix angles of bent yarns. A total of 28 plain weave woven fabrics (four groups, each with seven samples) were produced, using Solospun™ yarns as warp and weft threads. The fabric bending length and the initial modulus of each sample were measured from which the formability was calculated. Results indicated that the fabrics in which the warp and weft twists are unidirectional (Z & Z) have higher formability in comparison to those fabrics in which the warp and weft twists are opposite to each other (Z & S). In addition, among the former fabrics the highest formability belongs to those in which the total helix angle of the warp and weft is close to 90 degree whereas the lowest formability belongs to the latter fabrics with least amount of twist.

Geometric disposition of threads in single‐layer woven structures

PurposeThe purpose of this paper is to analyse the advantages of a new interpretation of the geometric disposition of threads within woven fabric structures, and to develop a method of determining the parameters of threads, with reference to each order of their disposition.Design/methodology/approachBased on the analysis of the geometrical models proposed by Barker and Midgely, by Pierce and by Novikov, the substantiation of the advantages of a stricter model, offered by the authors, for determining the geometric disposition of threads within single layer woven fabric structures with the help of the tangent function is given. This model allows the substantial expansion of the actual bounds of the interval of the order of the geometric disposition of threads in woven fabric structures to 0.2‐9.8.FindingsThe tangent function can approximate the crimp height ratio of the warp threads within the woven fabric structure with accuracy within the limits of geometric disposition angle change from 1° to 89°.Research limitations/implicationsThe work has applications in the industrial production of woven fabrics.Practical implicationsThis research will allow the design of a woven fabric with practically any ratio of crimp height for the warp and weft threads to effectively achieve the required performance characteristics of the cloth.Originality/valueThis paper extends the knowledge of the geometrical characteristics of woven fabric structure, and proposes intelligent methods of determining the parameters of thread cross‐sections in accordance with the orders of the geometric disposition of threads in woven fabric structure.

Oral History of McCreesh Place, Apartment Building for (Formerly) Homeless Men: Advancing the Warp and Balancing the Weave

Colors of gold, blue, green, and brown— Bold colors, timid colors, quiet colors, exotic colors— colors of the brave, and the weak. Like society’s discarded yarn, warp threads, tangled threads, they spin and choke, beaten and wound, balanced and counterbalanced and framed by handouts and handsup, until each voice clearly distinct and yet clearly different E- merges to create a new voice. A new voice. A new story. Our story. The story of McCreesh Place. Apartment building for (formerly) homeless men.

Use of regression methods for determining the relation between theoretical–linear and spectrophotometrical colour values of bicolour woven structures

In this paper, new approaches for evaluating the entire colour effect of optical mixing of bicolour woven structures are presented. Simple woven structures with constant colour in the warp direction and different colours in the weft direction were prepared and analysed. The constructional parameters of these woven fabrics were systematically changed, which resulted in the variations of the fractions of colour components and, consequently, also in the changes of colour properties (lightness, hue, chroma) of bicolour optical mixtures. The position of colours of the bicolour structures and the approximate direction (linear) of colour changes in CIELAB colour space were theoretically determined with a simple geometrical model and additive method. Furthermore, the bicolour optical effects were determined spectrophotometrically. The differences between the linear–theoretical and the spectrophotometrical colour values of bicolour woven fabrics were mathematically analysed with linear and non‐linear regression methods to determine the positions of colour coordinates L*, a* and b* of bicolour woven fabrics in the a*b* plane by increasing or reducing the cover factors of warp and weft threads (addition or reduction of colour components). The results present, on the one hand, the strong influence of original colours of warp and weft threads and, on the other hand, the minor influence of constructional parameters on the form of linear/non‐linear behaviour of colours of bicolour compositions. When the characteristics of a specific colour combination are taken into account, the spectrophotometrical colour values of bicolour woven fabrics can be also mathematically determined with additive–theoretical colour values and, to some extent, with predictable colour deviations.

Laboratory-based bidirectional reflectance distribution functions of radiometric tarps

Laboratory-based bidirectional reflectance distribution functions (BRDFs) of radiometric tarp samples used in the vicarious calibration of Earth remote sensing satellite instruments are presented in this paper. The results illustrate the BRDF dependence on the orientation of the tarps' weft and warp threads. The study was performed using the GSFC scatterometer at incident zenith angles of 0 degrees, 10 degrees, and 30 degrees; scatter zenith angles from 0 degrees to 60 degrees; and scatter azimuth angles of 0 degrees, 45 degrees, 90 degrees, 135 degrees, and 180 degrees. The wavelengths were 485 nm, 550 nm, 633 nm, and 800 nm. The tarp's weft and warp dependence on BRDF is well defined at all measurement geometries and wavelengths. The BRDF difference can be as high as 8% at 0 degrees incident angle and 12% at 30 degrees incident angle. The fitted BRDF data show a very small discrepancy from the measured ones. New data on the forward and backscatter properties of radiometric tarps are reported. The backward scatter is well pronounced for the white samples. The black sample has well-pronounced forward scatter. The provided BRDF characterization of radiometric tarps is an excellent reference for anyone interested in using tarps for radiometric calibrations. The results are NIST traceable.

Women's Work in Family, Village, and Town after 1000 CE: Contributions to Economic Growth?

This article is intended to expand current understandings of the commercial revolution of the medieval European economy by considering women's work as spinners of yarn and thread in the development of the medieval textile industry. Women's work in the central Middle Ages changed with the introduction of water-powered mills for grinding grain into flour for bread. As such water mills were introduced, women could turn to the preparation and spinning of wool into yarn. These female spinners or spinsters were both villagers and village-girls who had migrated to towns. Even with the introduction of the spinning wheel, spinning remained the great bottleneck in medieval textile production, because warp threads continued to be spun by hand. Thus, women's work in spinning wool and other fibers was central to the expansion of medieval European textile production.

A novel mechanism for driving the sley in a shuttle loom

In spite of extraordinary progress in the technology of weaving, the majority of weavers, particularly in the developing world, use shuttle looms. These looms suffer from various deficiencies, one of them being the severe abrasion between warp threads and shuttle, particularly when the shuttle leaves the shed. This can be avoided or reduced by allowing the sley to dwell near the back centre. Changing the drive of the sley from the currently used four-bar mechanism to a cam-driven mechanism will easily achieve this objective. However, weavers currently using shuttle looms are reluctant to accept this modification because of the significant increase in cost that it entails. A compromise would be a six-bar mechanism that can give a dwell or “near-dwell” condition, i.e. very slow motion, near the back centre. Such a mechanism, based on the Watt chain, has been explored in this article. It gives 0.06° of maximum angular displacement of the output link for 95° rotation of the input link. The suitability of the mechanism in satisfying the other requirements of sley movement of a shuttle loom has also been discussed.

A systematic approach towards the design of a multi-layered woven fabric: Modelling the structure of a multi-layered woven fabric

The objective of this paper was to develop an innovative method of description of the structure of a multi-layered woven fabric (MLWF). This method is based on a new way of classification of warp and weft threads into the groups of interweaving threads, which results in the fabric structure matrix. Modelling the MLWF by the fabric structure matrix has several advantages over traditionally used fabric weave matrix: (i) it enables the design of an MLWF to be reduced to the design of a single-layer woven fabric using appropriate CAD/CAM system; (ii) it provides a direct link between the design process and the technology of fabric production; (iii) the fabric structure matrix explicitly shows the weaves of the individual layers. Matrix equations were obtained that establish a two-way procedure for inter-transformation of weave matrix and structure matrices. The proposed method enables several different weaves of an MLWF to be designed that correspond to the same structure of the fabric. It is also possible to design fabrics with a given weave of the face and back layer, but different in stitching method used.

Shedding Without Dynamic Warp Loading: The Possibility of Forming a New Woven Structure

Shedding without dynamic warp loading is done by a loom using assemblies of polygonal shedding disks and disks for increasing weft density. The multiphase rotational loom allows completely new woven fabric structures to be manufactured, which until now was impossible to achieve using conventional looms. Woven fabrics can be manufactured with the use of warp and weft threads with extremely low tenacities, loose structures, and strong developed surfaces; as can grid structures and woven structures with pile loops. The possibility of utilizing unspinnable fibres, roving, and selvedges was demonstrated on a model of a multiphase rotational loom specially constructed for the tests.

3307 テキスタイル膜構造の三次元有限要素解析

We have developed the pseudo-continuum model to analyze the complicated nonlinear behavior of plain-weave fabrics within light computational task. This model homogenizes the fabric by means of a new definition of strain-displacement relationship that associates the microscopic deformation with the macroscopic one. This paper presents a new formulation to extend the pseudo-continuum model to three-dimensional problem. The covariant base vectors, which are defined on the convected coordinates parallel to the weft and warp threads, are employed to cope with the three-dimensional macroscopic deformation of the fabric. These vectors enable to easily define the thread strain as well as the two-dimensional problem. The finite element is formulated by the principle of virtual work in the total Lagrangian form. A numerical example concerning a simple tension membrane structure demonstrates the validity of the proposed formulation.

マニラ麻織物強化クロスプライ・グリーンコンポジットの引張特性

This paper deals with the tensile properties of Manila hemp fabric reinforced cross-ply “green” composites. The composites were made from woven Manila hemp fibers as the reinforcement and starch-based emulsion-type biodegradable polymer as the matrix. Experimental results showed that their flexural strength increased with increasing the fiber content. However, the tensile strength increased with the fiber content until nearly 50 mass% and leveled off thereafter. We found from the result of tensile tests that maximum tensile force of 0° ply sheets decreased with increasing the fiber content. This dependence on the fiber content is due to the decrease in the fiber strength caused by fiber's damages introduced during hot-pressing. In order to avoid the damage of fibers aligned in loading direction, fiber sheets were produced by using hemp fibers for warp and cotton threads for weft. As a result of using the cotton weft, the tensile strength of cross-ply “green” composites increased from 153MPa to 188MPa.

SHEDDING WITHOUT DYNAMIC WARP LOADING. THE POSSIBILITY OF FORMING A NEW WOVEN STRUCTURE.

Abstract The shedding without dynamic warp loading is presented by a loom structure with the use of assembles of multi-angle shedding disks, e.g. quadrangular shedding disks and disks for increasing weft density. Several sets of these assembles form the rotating weaving drum, which is electronically controlled. The new machine loom, the multi-layer rotational weaving machine, allows the manufacture of completely new woven fabric structures, which until now was impossible to achieve with the use of conventional weaving machines. Woven fabrics can be manufactured with the use of warp and weft threads of extremely low tenacity, loose structure and strong developed surface, as can grid structures and woven structures with pile loop. The possibility to utilise unspinnable yarn, roving and selvedges was demonstrated on a model weaving machine specially constructed for the tests.

The Measurement of the Tuft-withdrawal Force in Machine-made and Hand-knotted Carpet

An investigation is reported in which the tuft-withdrawal forces of five types of knot used in hand-knotted carpet were measured and compared. The results show that the tuft-withdrawal force varies with the type and complexity of the knot, and in particular with the total angle at which a tuft is wrapped around the warp threads. The Persian and Turkish knots were found to have similar tuft-withdrawal forces. The withdrawal force of the Spanish knot, which is of a simpler structure and is formed on one warp thread, was found to be far less secure than other knots having the same wrap angle (3π radians). The security of the knots is influenced by the reaction of the warp threads to the enveloping tuft, particularly when tension within the knot creates pressure between warp threads, as well as by the end from which the tuft was withdrawn. The Persian and Turkish knots and a new knot structure, designated the Kiwi knot, were recognised as ‘self-locking’ structures, having high tuft security.

The Geometry of the 2 × 2 Matt Weave Part I: Development of the Model

A study of the geometry of idealized 2×2 Matt Weave is carried out by proposing two simple models, namely point contact and distributive contact models based on a classical elastica approach, differing in the nature of the inter-yarn force active at the point of contact between bent and crossed threads. The models show that the presence of float in the weave makes the dimension of the unit cell thinner as compared to plain weave. The ratio of bending rigidities of the warp and weft threads becomes insignificant in crimp balance when the variable position of the point of contact is predominant.

Use of Scaling Theory for Determining the Breaking Load of Fabrics Made from Chemical Fibres

Empirical dependences are obtained for calculating the breaking load of fabrics made from viscose, polyester, and polyacrylonitrile yarn. Use of methods of scaling theory and dimensionality analysis make it much easier to find the functional type of multiparameter dependences. It was found that the breaking load of a fabric increases directly proportionally to the breaking load of the warp thread, number of warp threads, and type of weave.

Formation of Textile Structures for Giant-Area Applications

ABSTRACTRecently, textile machine manufacturers introduced to the market significant technological advances. Examples of such advances are higher speeds, higher level of automation, new concept of jacquard weaving that enables control of individual warp threads, CAD systems, and wider machines than seen before. This paper reviews the new development of formation systems of textile structures with emphasis on technologies that enables the production of giant-area fabrics. The review includes broad range of technologies (weaving, knitting, needlepunching, hydroentanglement, meltblowing, etc.). Additionally, the paper sheds the light on the potential of the textile technologies to manufacture electrotextile fabric structures.

Predicting Shrinkage in Polyester Reinforced by Glass Fabrics

Polyester is one of the most common resins used in contact lay-up method because of its low cost, room-temperature curing, wide availability, ease of handing, etc. However, the main disadvantage of this resin is the large volumetric shrinkage after curing (up to about 0.5%). This represents a major problem because it can cause unexpected defects in the molded composite parts such as warpage, distortion, rippled surface, etc. The effect of resin shrinkage on composite deformations is very complex because of the anisotropic properties induced by the fibers, especially in woven fabric composites with interlacing yarns. Moreover, in many applications, when the part geometry has a double curvature, the forming process usually results in significant in-plane shear deformation of the interlaced yams. The angle between the fill and the warp threads is no longer orthogonal because the fabric must follow the shape of the mold. In this work, an approach to measure the shrinkage coefficients of the interlaced yarns of fabric structure has been developed. The recently proposed sub-plies model has been used to predict deformations due to resin shrinkage in woven fabric composite. Resin shrinkage can lead to an expansion in the laminates with specific angles between undulated yams, due probably to a straightening effect on the fibers. Expansions due to matrix shrinkage were verified on several woven laminates. Prediction of deformations due to matrix shrinkage by the sub-plies model is in good agreement with experimental measurements.